The Mavic Crossmax XL S 29in Boost Wheelset Featuring a durable but lightweight aluminum rim and Mavic's exceptional Infinity hub, the Mavic Crossmax XL R 29in Boost Wheelset offers premium trail and enduro performance. Mavic Infinity hubs are lighter and stiffer than ever for enhanced performance, and they are set up with the InstantDrive 360 free for zero lag, putting power to the pedals. The ISM machining process eliminates excess weight for the best balance of durability and weight savings, and a 30mm internal width allows us to run tires up to 2. 5 inches wide. Another cool feature of the Mavic Crossmax XL is Mavic's Fore technology, which uses a sealed inner rim that eliminates the need for rim tape in a tubeless setup. Finally, Mavic's Black Shield technology helps protect against scratches and scuffs on the rims.